528 



THE GEOLOGIST, 



crossed on its middle third by numerous short parallel stripes of alternately light 

 and dark flint, and frequently terminated at each extremity by an irregular mass 

 of flint, often clouded or grey. The axis occurs sometimes isolated, sometimes 

 covered with a thin coating of grey flint only, and sometimes associated with only 

 a few cross stripes of the banded structure. In some instances the banded flint 

 has for its axis a sponge, or fragments of sponge. 



The author had not found in the banded flint any sponge-tissue peculiar to it ; 

 in some instances, however, a silicified sponge appears to have been traversed by 

 alternate lines of the light and dark colour analogous to those of the banded flints. 

 In some instances a concentric arrangement of light and dark layers of flint occur 

 around the two axes, or around isolated nuclei. Mr. Wetherell regarded this 

 banded appearance in the flint as not being due to an organic structure, but to 

 have originated in a peculiar arrangement of the siliceous matter around organic 

 bodies, frequently long and stem-like, such as those of the Graphularia which 

 supplied so many axial nuclei to the concretions in the London Clay. 



Nov. 17. — 5. "On some Fossils from South Africa." By Gr. W. Stow, Esq. 



At the close of 1850 Mr. Stow and his party fell back into the interior to avoid 

 the Kaffirs ; in making this journey he collected largely the fossils in his route, 

 and succeeded in preserving them on his return. In a plain at the foot of the 

 Rhenosterberg, which is a branch of Sneewbergen range, he met with patches of 

 ground strewed with nodular concretions and fossil wood, probably derived from 

 the neighboui'ing mountains. These mountains are composed of horizontal sti"ata. 

 Eight of the beds at the foot of the Rhenosterberg are sandstones ; above them are 

 four layers of calcareous grit, or pebbly limestone, with other sandstones. These 

 calcareous beds sometimes contain bones, but at one spot in the sandstone rock 

 Mr. Stow discovered and chiselled out a nearly perfect skeleton of a small reptile. 

 Other reptilian bones, and especially two small well-preserved skulls, rewarded his 

 search ; one of these belonged to a small Dicynodon, the other to a little unde- 

 scribed reptile. Mr, Stow sent numerous specimens of the numerous nodular 

 concretions and septaria from the rocks of this place, and also specimens of the 

 concretional and other trap-rocks of two dykes that crossed the plain. 



6. " On some Mineral Springs at Tehran, Persia." By the Hon, C, A. Murray. 

 The chief point in this paper was the description of the Ab-i-garm, a spring of 



hot water rising at about 2,000 feet above the bed of the river Laur, on one of 

 the spurs of the Demavend, a lofty and slumbering volcano. The principal mineral 

 ingredients in this water are sulphur and naphtha, and its temperature at its 

 source is about 150^^ F. 



7. "On Some Points in the Geology of South Africa," By Dr. R. N. Rubidge. 

 The author had observed in Namaqualand the occurrence of horizontal siliceous 



beds covering other siliceous inclined beds, the siliication of the latter being ap- 

 parently due to the infiltration of silica from the upper quartzose beds into the 

 inclined beds below. 



In this communication Dr. Rubidge details the evidences that he observed of 

 such a process having taken place, and points out how the observations on some of 

 the Namaqualand rocks by Mr, Bain, Mr. Bell, and Dr. Atherstone, respectively, 

 tend to support his views in this respect. The inclined beds of this district are 

 gneissic, and, in the instance referred to, very quartzose. The horizontal sandstone 

 of this district he correlates with the Table-mountain sandstones, but in them he 

 has found only a few obscure traces of fucoidal or other plants. 



The author then passes on to the Cape district ; and, first ofi'ering his testimony 

 to the industry and general exactitude of Mr. Bain as a geologist, he proceeds to 

 compare Mr, Bain's section of Mitchell's Pass with the section he made for him- 

 self on two hasty journeys. 



Mr, Bain describes the indurated sandstone or quartzite in Mitchell's Pass as 

 being, at first, horizontal, and then suddenly dipping at a short angle northward, 

 so as to underlie the Devonian Schists of the hokkeveld at Ceres, and to divide 

 them from the slates of the Cape district. Dr. Rubidge points out the apparent 

 difficulty of explaining such an inclination of the quartzite, the slates underlying 



